Means for and method of collecting



March 24, 1964 B. LINDER ETAL 3,125,847 MEANS FOR AND METHOD OFCOLLECTING STAPLE FIBERS Filed Feb.- 18, 1959 24 l4 3 24 o I 9 |9 7 2l84 l2 22 i I I III .LFJ 1 BERND LINDER EDWARD L.AHLSTROM INVENTORS BY wiwM ATT ORNEYS United States Patent 3,125,847 MEANS FOR AND METHOD OFCOLLECTING STAPLE FIBERS Bernd Linder, Belmont, and Edward L. Ahlstrom,Reading, Mass., assignors to Avco Manufacturing Corporation, Cincinnati,Ohio, a corporation of Delaware Filed Feb. 18, 1959, Ser. No. 794,026 20Claims. (Cl. 5758.89)

This invention relates to a method of and apparatus for collectingstaple fibers. While the invention is par ticularly suited forconverting silica fibers into rovings, its application is not limitedthereto and the process may be applied to glass, other thermoplasticmaterials, and mineral compositions, for example. The term roving isused herein as it is used in the textile field and describes a yarn-likeproduct in which the fibers are substantially parallel to each other.

Heretofore silica rovings were produced by combining a plurality ofextruded monofilaments of the basic silica material. Extruding silicamonofilaments is an extremely delicate operation requiring a high degreeof skill, and the production yield of the monofilaments is low, partlydue to the nature of the extrusion process and partly due to the carefulhandling required by the inherently brittle filaments.

It was found in practice that the techniques developed in making glassfibers and rovings could not be applied to silica because of itsextremely high melting temperature, as compared to that of glass.Materials suitable for containing molten silica, or working it in aplastic state, are not available.

In addition, the conventional methods of making both fibers and rovings,whether of silica or glass, are slow. In contrast, the novel inventionset forth herein produces both the fibers and the rovings at anextremely high rate beyond the capabilities of the prior art.

The fibers produced by the present process diifer from monofilaments inthat they have short finite lengths, in the order of two to four inches.Immediately after formation, the fibers are supported in a high velocitystream. Early attempts to collect these fibers from the stream and toconvert them into rovings by conventional textile carding techniquesfailed. Being inherently brittle, the silica fibers were destroyedduring carding by the attrition of the fibers rubbing together. Throughuse of the present invention it is possible to collect the short silicafibers from the stream and to transform them into an integrating rovingin a simple and inexpensive manner.

It is an object of the invention to provide a method of collectingstaple fibers which avoids one or more of the limitations anddisadvantages of prior methods.

It is another object of the invention to provide a method of andapparatus for converting staple fibers, as they are produced, directlyinto a roving.

It is still another object of the invention to provide an inexpensiveand efficient method of collecting staple fibers.

Other objects of the invention are:

(1) Utilization of a roving as a fiber collection medium foraccumulating staple fibers.

(2) Provision of means for coating the staple fibers prior to theirconversion into a roving.

(3) Provision of a method of making a roving in which the quantity ofroving produced is balanced against the quantity of fibers produced.

(4) Provision of a fiber collection method which makes use of the mutualadhesion between staple fibers.

(5) Provision of a fiber collection method particularly suited forcollecting staple fibers produced at a high rate.

(6) Provision of a method of producing a roving the cross section ofwhich may be varied and regulated.

The novel method of collecting staple fibers as a roving comprisessuspending the staple fibers in a fluid stream, preferably a highvelocity air stream, and spraying a lubricant into the stream forcoating the fibers. The fibers are then intercepted, causing them toadhere to one another to form an accumulation suspended in the fluidstream and extending in the direction of flow of the stream. Finally, aportion of the accumulation is continuously removed from the fluidstream without interrupting the collecting function of the accumulationthat remains within the fluid stream. The process is a continuous onewherein the accumulation acts as a collecting medium for newly formedfibers.

The novel features that are considered characteristic of the inventionare set forth in the appended claims; the invention itself, however,both as to its organization and method of operation, together withadditional objects and advantages thereof, will best be understood fromthe following description of a specific embodiment when read inconjunction with the accompanying drawings, in which:

FIGURE 1 is a top view of an apparatus for the making and collecting ofstaple fibers embodying the principles of this invention;

FIGURE 2 is a side view of the device shown in FIGURE 1; and

FIGURE 3 is a fragmentary enlarged view of a roving showing thealignment of the staple fibers therein.

Referring to FIGURES 1 and 2 of the drawings, there is shown anapparatus for making and collecting silica fibers. Shown is a fiberproducing means, comprising a ceramic metallizing gun 10, available as acommercial apparatus under the name of Mogul Turbo-jet Type R-l, made bythe Metallizing Company of America. The metallizing gun 10 softenssilica rod 11 and delivers the molten silica to a high velocity fluidstream, preferably a stream of air although steam is also suitable. Thehigh velocity fluid stream draws and attenuates the molten silica intofine staple fibers 9, in the order of two to four inches in length. Thedrawn staple fibers 9 emerge from nozzle 12 at the front of themetallizing gun along with the fluid stream. The staple fibers 9 arethus floated, or suspended, in the fluid stream and together with thefluid stream comprise a high velocity fiber stream 13. The metallizinggun 10 constitutes one means for producing a fiber stream and is notexhaustive of the devices available. For example, silica rod may bemelted and blown in a high temperature plasma are instead of metallizinggun 10.

As seen in FIGURES 1 and 2, the fiber stream 13 is directed outwardlyfrom the metallizing gun 10 and at a slightly elevated angle. Shortlyafter the fiber stream 13 leaves the metallizing gun 10, it passesthrough transverse lubricant sprays 14 in which the staple fibers arecoated with a suitable lubricant, a polyvinyl alcohol-oil emulsion forexample. The lubricant encourages adhesion between the staple fibers andalso tends to reduce abrasive breakage during collection when the fibersare moved relative to one another. The lubricant sprays comprise amixture of air and lubricant, and are formed by a pair of nozzles 16located adjacent to and pointing into the fiber stream. The lubricantsprays also tend to prevent the fiber stream 13 from dispersinglaterally.

After passing through the lubricant sprays 14, the fiber stream 13 isintercepted by a generally elongated body extending in the direction ofthe fiber stream 13. This horizontal body, hereinafter calledaccumulation 17, is suspended Within the air stream and extends througha funnel 18. The accumulation functions as a collection medium for thefibers suspended within the fiber stream 13. It intercepts these fibers,causing them to adhere to it and to one another. The adhesion iseffected partly by the natural aifinity the fibers have for one anotherand partly by the adhesive properties of the lubricant coating.

As seen in FIGURES l and 2 the accumulation buildup is nonuniform incross section. It is maximum at or near the funnel 18 and graduallytapers away to a vanishing point at an end 19 remote from the funnel 18.The fibers comprising the accumulation 17 are generally aligned in thedirection of the fluid stream. As a fiber 9 in the fluid stream 13comes, contacts and adheres to the accumulation, the fluid stream alignsit in the direction of the fluid flow. In the course of forming theaccumulation 17, a staple fiber in the fluid stream 13 first adheres toone or more fibers making up the accumulation 17 and then to newlyarrived fibers. The adhesion between fibers is manifestly great enoughto overcome the force of the high velocity fluid stream, and the resultis a selfsupporting build-up of aligned fibers which eventually form aroving.

The accumulation 17 at the mouth of the funnel 18 is outside of thefiber stream 113 and, therefore, no longer collects newly blown fibers.At this time, the accumulation may be considered to be a roving,designated for distinguishing purposes by the numeral 21. The roving 21passes from the funnel to a take-up means comprising a spool 22 which isrotated at a uniform rate by a motor assembly 25.

The take-up spool 22 exerts a constant force tending to withdraw theaccumulation 17 from the fiber stream 13- at a uniform rate. Thewithdrawal rate is adjusted so that the accumulation 17 collects fibersas fast as they are produced. It is obvious, that the cross section ofthe roving is a function of the withdrawal rate. In other words, if therotational speed of the take-up spool 22 is high, the accumulation 17passes through the fiber stream 13- in a small interval of time thusenabling it to collect only a small number of fibers. On the other hand,if the takeup velocity is low, the accumulation 17 is in contact withthe fiber stream for a greater length of time thus enabling it tointercept and collect a greater quantity of fibers. For the reasons justdiscussed the gauge, or width of the accumulation 17, and consequentlythe roving 21 is easily varied. It has also been found that when theWithdrawal velocity is kept constant, a roving having a uniform gauge isproduced.

The apparatus also includes auxiliary jets 23 which provide auxiliaryfluid streams 24 for maintaining the accumulation 17 in a substantiallyhorizontal position. Generally, the number of auxiliary jets employedand their location relative to the fluid stream 13 will vary with theapparatus employed to practice the invention and the nature of the fluidavailable. Both of these considerations are easily handled by a skilledpractitioner. The auxiliary fluid streams 24 also have the effect offocusing the fiber stream 13 in a horizontal direction and preventing itfrom dispersing. T hus auxiliary fluid streams 24, in conjunction withthe previously described lubricating sprays "14, tend to prevent thefiber stream 13 from dispersing and to channel it, and the fibers 9=suspended therein in particular, into contact with accumulation 17. Theauxiliary fluid streams 24 merge with the fiber stream 13 to form acomposite stream in which the staple fibers are suspended and in whichthe accumulation is suspended and its position stabilized.

The accumulation 17 responds to the dominant forces in the compositestream of fluid and assumes a cantilevered construction extending in thedirection of the composite stream. In FIGURE 2 it is apparent that thecomposite stream and accumulation extend in a horizontal direction.

The direction of the composite stream diifers from the fiber stream 13due to the placement of the auxiliary jets 23, as indicated in FIGURES 1and 2, and interaction of the auxiliary fluid streams 24 and the fiberstream 13 4 whether turbulence exists in the composite stream isimmaterial so long as the dominant force develops a composite streammoving linearly.

The apparatus for and method of collecting fibers just describedcomprises a simple, inexpensive system for collecting staple silicafibers into a roving. In FIGURE 3 of the drawings, there is shown agreatly enlarged representation of a section of roving. It will be notedthat the staple fibers therein are longitudinally aligned. In convertingthe blown fibers directly into a roving the normal intermediate cardingstep is eliminated.

This is particularly significant when working with silica because of theabrasive nature of the material. In a carding operation, a randomaccumulation of fibers is converted to a generally aligned accumulation.The process involves a great deal of relative movement betweencontiguous fibers, much of which occurs in a transverse direction. Thefine fibers act as cutting edges tending to weaken or cut through thefibers. In the process disclosed herein the relative movement occursbetween substantially parallel fibers, a condition which minimizes thecutting effect between fibers.

It has also been found that the process is operable and effective if thefibers are not lubricated prior to their collection. However, a rovingcomprising nonlubricated fibers has been found to be somewhat weaker intensile strength than one containing lubricated fibers.

It is clear from the foregoing description and operation that theprocess is a balanced and continuous one. The fibers are collected asthey are formed and the accumulatfiion 17 acts as a collecting mediumfor the newly blown 1 bers.

To complete this discussion it is merely necessary to indicate how theprocess is initiated. To initiate the process, the metallizing gun, thelubricant spray and the auxiliary spray are first activated. A rod, notshown, is then inserted through the large opening of the funnel 18 andout of the small opening and into the fiber stream 13. The rod acts, atthis time, as the collection medium and the fibers in the fiber stream13 adhere to it and to themselves to form an accumulation 17. The rod isthen slowly withdrawn from the fiber stream without removing the formedaccumulation 17 from the fiber stream 13 and without interrupting itscollecting function. After the rod is removed from the funnel 18, theroving connected to it is removed and wound on the take-up spool 22.Thereafter the process becomes a self-supporting and contmuous one.

The various features and advantages of the invention are thought to beclear from the foregoing description. Various other features andadvantages not specifically enumerated will undoubtedly occur to thoseversed in the art, as likewise will many variations and modifications ofthe preferred embodiment illustrated, all of which may be achievedwithout departing from the spirit and scope of the invention as definedby the following claims.

We claim:

1. A method of collecting staple fibers as a roving compr1s1ng:suspending the fibers in a linearly directed nonrotational fluid stream;intercepting the fibers in the stream; and causing them to adhere to oneanother in a substantially linear parallel relationship and to form anaccumulation suspended by the fluid stream.

2. A method of collecting staple fibers as a roving as described inclaim 1 in which said fluid stream is a high velocity gas.

3. A method of collecting staple fibers as a roving comprising:suspending the fibers in a linearly directed nondirection Opposite tothe direction of the fluid is formed whereby a roving is produced.

4. A method of collecting staple fibers as a roving comprising:suspending the fibers in a linearly directed nonrotational fluid stream;injecting a lubricant into the fluid stream for coating the fibers;intercepting the fibers in the fluid stream causing them to adhere toone another in a substantially linear parallel relationship and to forman elongated accumulation suspended in the fluid stream; supporting oneend of said accumulation to maintain it in a fixed position in the fluidstream and suspended thereby; directing auxiliary fluid streams into thefirst mentioned fluid stream for focusing the fibers against saidaccumulation; and continuously withdrawing a portion of the accumulationin a direction opposite to the direction of flow of the first mentionedfluid stream at a preselected rate for forming a roving having apredetermined gauge.

5. A method of making and collecting silica fibers as a rovingcomprising; supplying silica to a metallizing gun for melting the silicaand attenuating the molten silica into staple fibers by spraying themelt out of the gun in a high velocity nonrotational air stream, thefibers being suspended in the air stream; spraying a mixture of air andlubricant into the air stream for coating the fibers; intercepting thefibers causing them to adhere to one another in a substantially linearparallel relationship to form an accumulation; supporting theaccumulation by the air stream to continuously intercept silica fibers;and continuously withdrawing a portion of the accumulation in adirection opposite to the direction of flow of the air stream to form acontinuous roving.

6. A method of making and collecting silica fibers as a roving asdescribed in claim 5 which includes, in addition, directing an auxiliaryfluid stream into the air stream for focusing the silica fibers on theaccumulation.

7. A method of collecting staple fibers as a roving comprising: forminga jet of fluid; suspending staple fibers in said jet of fluid; andintercepting said staple fibers in said jet of fluid as a continuousaccumulation.

8. A method of collecting staple fibers as a roving comprising: forminga jet of fluid; suspending staple fibers in said jet of fluid; andinserting means in said jet of fluid for intercepting said fiberscausing them to adhere to said means as a continuous accumulationsuspended in the jet of fluid.

9. A method of collecting staple fibers as a roving comprising: forminga jet of fluid; suspending staple fibers in said jet of fluid;intercepting said staple fibers in said jet of fluid causing them toadhere to one another and to form an accumulation; and slowlywithdrawing said accumulation in a direction opposite to the directionof flow of said jet of fluid without interrupting the collection offibers.

10. A method of collecting staple fibers as a roving comprising: forminga first nonrotational stream of fluid; suspending staple fibers in saidfirst nonrotational stream of fluid; directing a second nonrotationalstream of fluid against said first stream of fluid to reduce dispersionof said staple fibers; and intercepting said staple fibers andcollecting them in an accumulation.

11. A method of collecting staple fibers comprising: forming a firstnonrotational stream of fluid; suspending staple fibers in said firstnonrotational stream of fluid; directing a second nonrotational streamof fluid against said first nonrotational stream of fluid to linearlycollimate said staple fibers; intercepting said staple fibers causingthem to form an accumulation; and removing the accumulation from saidfirst nonrotational stream of fluid in a direction opposite to thedirection of flow of said first nonrotational stream of fluid withoutinterrupting the accumulation of fibers.

12. A method of collecting staple fibers as a roving comprising:suspending staple fibers in a substantially laminar stream of fluid;intercepting said staple fibers and collecting them in an accumulation;and directing a sec- 0nd stream of fluid against said laminar stream offluid tending to move said suspended fibers into contact with saidaccumulation.

13. A method of making and collecting silica fibers as a rovingcomprising: melting silica and attenuating the molten silica into staplefibers by the interaction of the molten silica and a high velocity,nonrotational .fluid stream, the fibers formed thereby being suspendedwithin said fluid stream; directing auxiliary streams of fluid on saidfiber stream for preventing the dispersion of the fibers, said fiberstream and said auxiliary stream of fluid merging into a compositestream of fluid; inserting means in the composite stream of fluid forintercepting the silica fibers, causing them to adhere to the means andto one another; withdrawing the collecting medium from the compositestream of fluid at a rate which permits newly formed fibers to beintercepted by the previously collected fibers to form an accumulationsuspended by and stabilized in position by said composite stream offluid; continuously withdrawing a portion of the accumulation from thecomposite stream of fluid in a direction opposite to the direction offlow of the composite stream of fluid while the remaining portion of theaccumulation in the composite stream of fluid continues to collect newlyformed fibers; and winding the accumulation on a collection spool.

14. A method of collecting staple fibers as a roving comprising: forminga first jet of fluid; suspending staple fibers in said first jet offluid directing a second jet of fluid against the said first jet offluid for reducing dispersion of said staple fibers, said first andsecond jets of fluid forming a composite jet of fluid having said staplefibers suspended therein; intercepting said staple fibers in saidcomposite jet of fluid causing them to form a continuous accumulation;and slowly withdrawing said accumulation in a direction opposite to thedirection of flow of the composite jet of fluid without interrupting theaccumulation of fibers.

15. A method of collecting staple fibers as a roving comprising:suspending staple fibers in a first jet of fluid; directing a second jetof fluid against said first jet of fluid to reduce dispersion of saidsuspended fibers, said first and second jets of fluid merging into acomposite jet of fluid; and intercepting said staple fibers in saidcomposite stream of fluid causing them to form an accumulation.

16. An apparatus utilizing a fiber accumulation for collecting staplefibers as a roving comprising: means for forming a stable fibersuspension in a jet fluid stream,

guide means for supporting the fiber accumulation in suspension Withinthe jet fluid stream for intercepting the suspended fibers in asubstantially parallel relationship; and take-up means adapted tocontinuously withdraw a portion of the fiber accumulation from the jetfluid stream in a direction opposite to the direction of flow of jetfluid stream without interrupting the fiber intercepting function of theremaining portion.

17. An apparatus utilizing a fiber accumulation for collecting staplefibers as a roving comprising: means for forming a staple fibersuspension in a jet of fluid; guide means for slidably supporting oneend of the fiber accumulation, said other end being in suspension withinthe jet of fluid and supported thereby for intercepting the suspendedfibers; and take-up means adapted to continuously withdraw a portion ofthe fiber accumulation from the jet of fluid in a direction opposite tothe direction of flow of the jet of fluid without interrupting the fiberintercepting function of the remaining portion.

18 An apparatus utilizing a fiber accumulation for collecting staplefibers as a roving comprising: means for forming a stable fibersuspension in a first jet of fluid; means for directing a second jet offluid against the first jet of fluid for preventing the dispersion ofthe fibers suspended in the latter, said first and second jets of fluidmerging into a composite jet of fluid; and guide means for slidablysupporting one end of the fiber accumulation,

said other end being suspended in said composite jet of fluid andsupported thereby, for intercepting the suspended fibers.

19. An apparatus as described in claim 18 in which said second jet offluid is directed laterally into said first stream of fluid, andincludes a component of velocity in the direction of flow of said firststream of fluid.

20. An apparatus for collecting staple fibers as a roving comprising:means for forming a stable fiber suspension in a nonrotational stream offluid; auxiliary fluid means interacting with said nonrotational streamof fluid to form a composite nonrotational stream of fluid for reducingdispersion of said fibers suspended in said nonrotational stream offluid; and guide means for slidably supporting one end of the fiberaccumulation, said other end being inserted in said composite stream offluid for intercepting fibers therein forming an accumulation.

References Cited in the file of this patent UNITED STATES PATENTS2,451,504 Mayo Oct. 19, 1948 2,686,954 Parker Aug. 24, 1954 2,787,314Anderson Apr. 2, 1957 2,801,189 Collier July 30, 1957 2,911,783Gotzfried Nov. 10, 1959 2,931,421 Schuller Apr. 5, 1960 FOREIGN PATENTS536,990 Canada Feb. 12, 1957 536,991 Canada Feb. 12, 1957

13. A METHOD OF MAKING AND COLLECTING SILICA FIBERS AS A ROVINGCOMPRISING: MELTING SILICA AND ATTENUATING THE MOLTEN SILICA INTO STAPLEFIBERS BY THE INTERACTION OF THE MOLTEN SILICA AND A HIGH VELOCITY,NONROTATIONAL FLUID STREAM, THE FIBERS FORMED THEREBY BEING SUSPENDEDWITHIN SAID FLUID STREAM; DIRECTING AUXLIARY STREAMS OF FLUID ON SAIDFIBER STREAM FOR PREVENTING THE DISPERSION OF THE FIBERS, SAID FIBERSTREAM AND SAID AUXILIARY STREAM OF FLUID MERGING INTO A COMPOSITESTREAM OF FLUID; INSERTING MEANS IN THE COMPOSITE STREAM OF FLUID FORINTERCEPTING THE SILICA FIBERS, CAUSING THEM TO ADHERE TO THE MEANS ANDTO ONE ANOTHER; WITHDRAWING THE COLLECTING MEDIUM FROM THE COMPOSITESTREAM OF FLUID AT A RATE WHICH PERMITS NEWLY FORMED FIBERS TO BEINTERCEPTED BY THE PREVIOUSLY COLLECTED FIBERS TO FORM AN ACCUMULATIONSUSPENDED BY AND STABILIZED IN POSITION BY SAID COMPOSITE STREAM OFFLUID; CONTINUOUSLY WITHDRAWING A PORTION OF THE ACCUMULATION FROM THECOMPOSITE STEAM OF FLUID IN A DIRECTION OPPOSITE TO THE DIRECTION OFFLOW OF THE COMPOSITE STREAM OF FLUID WHILE THE REMAINING PORTION OF THEACCUMULATION IN THE COMPOSITE STREAM OF FLUID CONTINUES TO COLLECT NEWLYFORMED FIBERS; AND WINDING THE ACCUMULATION ON A COLLECTION SPOOL.